refactor(agent-loop): simplify message machine

packages/subagent/subagent-inprocess/src/index.ts

@@ -10,7 +10,7 @@
 import { randomUUID } from 'node:crypto'
 import type { Context } from 'cordis'
 import type { Agent, AgentOptions } from '@deepseek-ai/dsh-agent'
-import { findLastMessageTurnEnd, SessionId, type SessionEvent, type TurnEndReason } from '@deepseek-ai/dsh-session'
+import { SessionId, type SessionEvent, type TurnEndReason } from '@deepseek-ai/dsh-session'
 import { createUserMessage, type ContentBlock } from '@deepseek-ai/dsh-llm'
 import { assertSubagentMaxDepth, delegationDepthOf } from '@deepseek-ai/dsh-subagent'
 import type { SubagentResult, SubagentRun, SubagentStartRequest, SubagentStopReason } from '@deepseek-ai/dsh-subagent'
@@ -47,7 +47,6 @@ function toStopReason(reason: TurnEndReason | undefined): SubagentStopReason {
     case 'aborted':
       return 'aborted'
     case 'error':
-    case 'disposed':
     case 'interrupted':
     default:
       return 'error'
@@ -160,7 +159,8 @@ export async function startInProcessRun(
 
   const result: Promise<SubagentResult> = (async () => {
     try {
-      child.followup(createUserMessage({ content: request.prompt, source: { kind: 'user' } }))
+      const message = createUserMessage({ content: request.prompt, source: { kind: 'user' } })
+      child.followup(message)
       await child.whenIdle()
       return readResult(
         child,
@@ -194,12 +194,11 @@ function readResult(
 ): SubagentResult {
   const own = child.session.events.slice(seedLength)
   const lastMessage = own.findLast((event): event is SessionEvent<'assistant/message'> => event.type === 'assistant/message')
-  const lastEnd = findLastMessageTurnEnd(own)
+  const lastEnd = own.findLast((event): event is SessionEvent<'turn/end'> => event.type === 'turn/end')
   const output: ContentBlock[] = lastMessage?.data.message.content ?? []
   const recorded = toStopReason(lastEnd?.data.reason)
-  // Disposal can tear the owner down before the loop records its ordinary
-  // `aborted` end, yielding `disposed` instead. A requested cancellation owns
-  // every non-completed in-flight outcome; a turn already completed stays so.
+  // A requested cancellation owns every non-completed in-flight outcome; a
+  // turn already completed stays so.
   const stopReason: SubagentStopReason = cancelled && recorded !== 'completed'
     ? 'aborted'
     : recorded

packages/subagent/subagent-inprocess/tests/subagent-inprocess.spec.ts

@@ -56,34 +56,27 @@ describe('startInProcessRun', () => {
     expect(ctx.agents.get(run.id)).toBeUndefined()
   })
 
-  it('reports the message-turn outcome when a later non-message turn completes during flush', async () => {
-    const { ctx, parent } = await setup([maxTokensResponse('partial answer')])
-    let injected = false
-    ctx.on('session/flush', (session) => {
-      if (injected || session.header.parentSession === undefined) return
-      const lastEnd = session.events.findLast(event => event.type === 'turn/end')
-      if (lastEnd?.type !== 'turn/end' || lastEnd.data.reason.kind !== 'max-tokens') return
-      injected = true
-      const turn = lastEnd.data.turn + 1
-      session.append('turn/start', {
-        turn,
-        trigger: { kind: 'injection', source: { kind: 'plugin', plugin: 'late-metadata' } },
-      })
-      session.append('user/message', createUserMessage({
-        content: [{ type: 'text', text: 'late metadata' }],
-        source: { kind: 'plugin', plugin: 'late-metadata' },
-      }), { surfaceOp: 'append' })
-      session.append('turn/end', { turn, reason: { kind: 'completed' } })
+  it('reports the final whole-agent outcome after idle replacement work', async () => {
+    const { ctx, parent } = await setup([maxTokensResponse('partial answer'), textResponse('replacement answer')])
+    let replaced = false
+    ctx.on('agent/status', (agent, status) => {
+      if (replaced || status !== 'idle' || agent.session.header.parentSession === undefined) return
+      replaced = true
+      agent.followup(createUserMessage({
+        content: [{ type: 'text', text: 'replacement work' }],
+        source: { kind: 'plugin', plugin: 'replacement' },
+      }))
     })
 
     const run = await startInProcessRun(request(parent), {})
     const result = await run.result
     const child = ctx.agents.get(run.id)!
 
-    expect(injected).toBe(true)
+    expect(replaced).toBe(true)
     expect(child.session.events.findLast(event => event.type === 'turn/end'))
       .toMatchObject({ data: { reason: { kind: 'completed' } } })
-    expect(result.stopReason).toBe('max-tokens')
+    expect(result.stopReason).toBe('completed')
+    expect(text(result.output)).toBe('replacement answer')
     await run.dispose()
   })